Apps crash with 0xc0000135, Sophos causes BSODs

May’s mandatory security update silently disabled .NET 3.5 Framework, causing a cascade of application launch failures with error 0xc0000135. ProtonVPN, PowerShell, Event Viewer, KeePass, Visual Studio, Discord, ShareX, and Teams all refused to open. As a delightful bonus, machines running Sophos Home antivirus got BSODs from the hmpalert.sys driver. A security update that breaks your VPN, your password manager, your IDE, your chat app, AND your antivirus — that’s efficiency.